The Chance Vought Aircraft RGM-15 Regulus II cruise missile, which
could carry a 2,920-pound nuclear warhead at Mach 2 supersonic speed, first
flew in May 1956, from Edwards Air Force Base, and was intended to be a
replacement for the Regulus I cruisle missile, which first entered service
in 1955, on the cruiser USS Los Angeles (CA-135), though the aircraft
carrier
USS Princeton (CV 37) was the first ship to fire it. It
was later deployed on three other cruisers, the USS Helena (CA 75),
the USS Macon (CA 132), and the USS Toledo (CA 133), ten
aircraft carriers, and five submarines, the USS Barbero (SSG-317),
the USS Grayback (SSG-574), the USS Halibut (SSGN-587), the
USS
Tunny (SSG-282), and the USS Growler (SSG-577), which is now,
with a Regulus I missile, on display at the Intrepid Air Sea Space Museum,
in New York City. Once fired, the Regulus I cruise missile could be guided
to its target, by a pilot, from a range of 125 miles, at 35,000 feet. However,
the Regulus II cruise missile project was cancelled on December 18, 1958,
as the United States Navy decided to develop the submarine-launched Polaris
ballistic missile, instead, and the Regulus I cruise missile remained in
service until 1964, on the USS Halibut, with 514 of them being built.

The 11-ton Regulus II cruise missile, which was powered by a General
Electric J79 jet engine, had a wingspan of 20 feet and 1 inch (6.12 meters),
a length of 57 feet and 6 inches (17.5 meters), a range of 1,380 miles
(2,220 km), and 54 of them were built. The only submarine-based firing
of the Regulus II cruise missile, from the USS Grayback, occurred
in September 1958 and some of these were still in use by the USN after
1958, as reuseable supersonic target drones, equiped with landing gear.

These photos show some of the Regulus II cruise missiles being used
as target drones for Bomarc missiles, at the Eglin Gulf Test Range, which
was adjacent to the Venice Municipal Airport, in Venice, Florida. They
would be flown at supersonic speed to Eglin Air Force Base, during these
training flights for Bomarc crewmembers, and surface-to-air Bomarc missiles,
with a top speed of Mach 2.8 and a range of 250 miles, would be fired from
Santa Rosa Island, in Florida, which was under the command of the Montgomery
Air Defense Sector, at Gunter Air Force Base, in Alabama, about 150 miles
away, to track them down.

The first Regulus II target drone flight from this test range was
made on September 3, 1959 and a total of 46 flights were made, using 13
missiles. These operations were later moved to the United States Navy's
Naval Air Station Roosevelt Roads, in Puerto Rico, on September 30, 1961,
where they were used as target drones for Tartar, Terrier, and Talos missiles,
until 1963. Most of the Regulus II target drones, which were designated
KD2U-1 and MQM-15A, were used at Point Mugu, California, where 17 target
drones made 64 flights and the last Regulus II target drone flight was
made by GM2048 in December 1965.